The invention relates to the field of gas turbine engines, and more specifically, to an improved gas turbine engine using a rotating fluid flow train to feed the combustor and enhance air/fuel mixing and emissions.
A type of prior art gas turbine engine has a compressor, a fuel source, a combustion air source, a casing, and a combustor to prepare a heated fluid from fuel and combustion air. The combustor is connected to the fuel source, the combustion air source and the compressor. Practically the entire fluid flow from the compressor is directed to the combustor. The engine has a turbine rotor disk with blades that receive the heated fluid from the combustor. As the turbine rotor disk rotates during engine operation, the heated fluid flow coming from the combustor has to be directed at an angle to the blades to ensure smooth entry conditions. This is done using stator vanes that are positioned at a certain angle and direct the heated fluid from the combustor to the turbine rotor disk in a manner compatible with rotor disk rotation. This gas turbine engine is disclosed in U.S. Pat. No. 3,826,084 to Branstrom et al.
The stator vane angle normally is chosen to accommodate the most optimum and prevailing turbine rotor disk operating conditions (speed). This solution is quite acceptable for gas turbine engines that have more or less stable operating conditions, such as when used for power generation. In applications where the load upon the gas turbine engine is steady, the turbine rotor disk rotates at a stable speed, and the entry angle for the blades remains unchanged thus minimizing losses. If, on the other hand, this gas turbine engine is used to power a vehicle, the situation is radically different. In that application, the turbine rotor disk speed will vary within a broad range depending on vehicle load. Consequently, the entry angle also varies within a broad range under load fluctuations, which leads to greater losses. This problem could not be solved by using the conventional approach with the stator vanes. It is possible to use controllable stator vanes to change the entry angle at the blades, but it is a very complicated and expensive solution given the high temperatures downstream of the combustor and space limitations. As a result, the gas turbine engine would have high losses in vehicle applications. Moreover, the stator and vanes occupies an additional space and makes the engine design more complicated and expensive. The use of controllable vanes makes the engine less reliable.
The problems indicated above are solved in the gas turbine engine of this invention.
It is an object of the invention to provide a gas turbine engine of the above type that has a higher efficiency.
Another object of the invention is to provide a more compact gas turbine engine that has a simpler design.
Another object of the invention is to improve the emission characteristics of the gas turbine engine.
A gas turbine engine has a device to admit a rotating fluid flow from an annular space in the casing to the inlet portion of a combustor to form a rotating fluid flow in the inlet portion of the combustor. The rotating fluid flow is formed in the annular space of the casing by supplying a fluid from a compressor to the blades of the turbine rotor disk.
Other objects and advantages of the invention will become apparent from the following detailed description of preferred embodiments and accompanying drawings.